The Sun: just a star, like many others...
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Sunspot.jpgSunspots' Region 87571 visiteCaption NASA originale (da "NASA - Picture of the Day" del 2 Maggio 2006):"An unusually active Sunspot Region is now crossing the Sun.
The Region, numbered 875, is larger than the Earth and has produced several Solar Flares over the past week. It should take a few more days for Sunspot 875 to finish crossing the solar disk. The above image of the Sun was taken last Wednesday in a very specific color of red light to bring up detail. Sunspot 875, in the midst of erupting a large "Class C" Solar Flare, can be seen as the dark region to the upper right. In the above image, relatively cool regions appear dark while hot regions appear bright.
On the far left, solar prominences are visible hovering above the Sun's surface".
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Sunspots - SST.jpgSunspots66 visiteCaption NASA originale:"This stunning image shows remarkable and mysterious details near the dark central region of a planet-sized sunspot in one of the sharpest views ever of the surface of the Sun. Just released, the picture was made using the Swedish Solar Telescope now in its first year of operation on the Canary Island of La Palma. Along with features described as hairs and canals are dark cores visible within the bright filaments that extend into the sunspot, representing previously unknown and unexplored solar phenomena".
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Sunspots-090602.jpgSunspots and Clouds in Solar Cycle 2453 visiteDa "NASA - Picture of the Day" del giorno 4 Giugno 2009:"On June 2nd, 2009, clouds over Stuttgart, Germany parted to reveal what has become a relatively rare sight, spots on the Sun. In fact, the roughly 11-year solar activity cycle is still in a surprisingly deep minimum and the years 2008 and 2009 have had the lowest Sunspot counts since the 1950s. Even the latest prediction is that the new cycle, Solar Cycle 24, will reach a maximum in May 2013 with a below-average sunspot count. The Solar Cycle 24 Sunspots recorded here are in active region AR 1019.
Previously, only two cycle 24 active regions with Sunspots, AR 1018 and AR 1017, were seen in May".MareKromium
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Sunspots-EB-LXTT.jpgSummer 2011's Sunspots (by Elisabetta Bonora - Lunexit Team)199 visitenessun commentoMareKromium
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Sunspot~0.jpgAn Active Sunspot Viewed Sideways53 visiteCaption NASA:"Why are there dark spots on the Sun? Although noted for thousands of years, sunspots have been known for decades to be regions of the Sun that are slightly depressed and cooled by the Sun's complex and changing Magnetic Field.
High resolution pictures like the above image from Japan's new Sun-watching Hinode satellite, however, are helping to increase modern understanding. In the center of the above image is a sunspot, but not seen in the usual orientation - this sunspot is seen sideways.
Of particular interest is erupting glowing gas that shows how the Sun's Magnetic Field comes right out of the spot center, but curves markedly around the spot edges. Better understanding of how the Sun ejects particles into space may result in more accurate predictions of solar storms that affect satellites, astronauts and even power grids on Earth".
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The Solar Spectrum_noao.jpgThe Solar Spectrum and the "missing colors"...56 visiteDa "NASA - Picture of the Day" del 27 Febbraio 2005:"It is still not known why the Sun's light is missing some colors. Shown above are all the visible colors of the Sun, produced by passing the Sun's light through a prism-like device. The above spectrum was created at the McMath-Pierce Solar Observatory and shows, first off, that although our yellow-appearing Sun emits light of nearly every color, it does indeed appear brightest in yellow-green light. The dark patches in the above spectrum arise from gas at or above the Sun's surface absorbing sunlight emitted below. Since different types of gas absorb different colors of light, it is possible to determine what gasses compose the Sun. Helium, for example, was first discovered in 1870 on a solar spectrum and only later found here on Earth. Today, the majority of spectral absorption lines have been identified - but not all".
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The Sun from SOHO.jpgAnagliph of the Sun54 visitenessun commento
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The Sun from Soho.jpgA "Solar Prominence" from Soho62 visiteCaption NASA originale:"A 'Solar Prominence' is a cloud of solar gas held above the Sun's surface by the Sun's magnetic field. The Earth would easily fit under the hovering curtain of hot gas (like the one pictured above). A quiescent prominence typically lasts about one month, and may erupt in a Coronal Mass Ejection (CME) expelling hot gas into the Solar System. Although somehow related to the Sun's changing magnetic field, the energy mechanism that creates and sustains a Solar Prominence is still a mistery".
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The Sun in Hydrogen-Alpha light (2).jpgThe Sun in Hydrogen-Alpha light56 visiteCaption NASA originale:"The above image, taken in a single color of light called Hydrogen Alpha, records a great amount of detail of the simmering surface of our parent star. The gradual darkening towards the Sun's edge, called limb darkening, is caused by increased absorption of relatively cool solar gas. Further over the edge, a giant prominence is visible, while a different prominence can be seen in silhouette as the dark streak near the image center. Two active areas of the Sun are marked by bright plages. The above amateur photograph of the Sun was taken just through a small telescope and a standard digital camera".
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The Sun in Hydrogen-Alpha light.jpgThe Sun in "Hydrogen-alpha" light84 visiteCaption NASA originale:"The above picture was taken in a specific color of light emitted by Hydrogen gas called Hydrogen-alpha. Granules cover the solar photosphere surface like shag carpet, interrupted by bright regions containing dark sunspots. Our Sun glows because it is hot, but it is NOT on fire. Fire is the rapid acquisition of oxygen, and there is VERY LITTLE O2 on the Sun! The energy source of the Sun is the nuclear fusion of Hydrogen into Helium (4H--->1He) deep within its core".
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The Sun-20031202_c2_EIT304.jpgOur "restless" Sun... (1)53 visitenessun commento
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The Sun-C2_EIT_Nov8_00G.jpgOur "restless" Sun... (2)53 visitenessun commento
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